CA2180578A1 - Impedance controlled interconnection device - Google Patents

Abstract

An interconnection device for interconnecting a number of first terminals to a number of second terminals. The interconnection device includes a conductive housing and a number of contacts that are insulated from the conductive housing. This configuration may provide shielding to the number of contacts from outside sources of electro-magnetic interference. Further, a number of conductive ribs may be provided between adjacent contacts, thereby shielding the contacts from cross-talk interference between adjacent contacts. Finally, the impedance of each contact in the interconnection device may be controlled to provide a stable bandpass, and may be programmable to match, or correct for, the input impedance of a corresponding device.

Description

.
IM~EDANCE CONTRO1LED ~~ lON DEVICE
Technical Field The prefient invention deals broadly with the field of devices for interconnecting electrical contacts. More narrowly, however, oS the invention is related to technology for inter-connecting a plurality of corresponding terminals by means of an electrical conductor between an integrated circuit device and a printed circuit board or between two printed circuit boards. The device is particularly useful for interfacing an integrated circuit with a 10 te8ter, including a printed circuit board, during the manufacturing process to assure operativeness. The preferred embodiments of the present invention are directed to means for controlling the impedance and/or providing shielding to the interconnection between devices .
Backqround of the Invention Devices and methods for effecting electrical interconnection between two conductors are generally known. A ~p~ 1 i 7ed area of such interconnection has been recently expanding with the advent of integrated circuit technology. For example, in the manufacturing 20 process for fabricating integrated circuit devices, each integrated circuit must be tested for operativeness. Thus, each lead of an integrated circuit device must be interconnected with a tester apparatus, wherein the tester apparatus may determine the functionality and performance of the corresponding integrated 25 circuit device.
During such testing, an integrated circuit device is typically .
placed into an interconnect device ( such as a test socket ) . The interconnect device interconnects each lead of the integrated circuit with a ~,o~ onding terminal of a printed circuit board.
This may be Al-_ ~ 1 i Chl~d with a number of contacts within the 05 interconnect device. A tester apparatus is then electrically coupled to the printed circuit board such that the signals provided to each lead of the integrated circuit may be controlled and/or observed by the tester apparatus.
further spe~i Al i '7 d area of interconnecting electrical 10 contacts focuses on the interconnection of two printed circuit boards. These interconnections have applications utilizing insertable ~oards, such as memory cards, or multi-chip boards which are highly miniaturized and integrated.
Several technologies for packaging an integrated circuit chip L5 into an semi-conductor package have been developed. These may be generally categorized as pin grid array (PGA) systems and leaded semi-conductor devices. The leaded semi-conductor devices include plastic leaded chip carriers ( P~CC ), dual in-line package~ ( DIP ) and Quad Flat Pack ~QFP). ~ach packaging type requires a 20 particular array of leads to be interconnected with a printed circuit board.
A number of methods for connecting integrated circuits, such as PGA devices, with a printed circuit board are known. It i~
believed that limitations to these systems are the contact length 25 and the usual requireme~t of mounting the contacts in through-holes located in a printed circuit board. The contact and through-hole

2 ~ 8057~
.
mounting limits the mounting speed of the semi-conductor device while i n~lllrin~ discontinuities and impedance which cause signal reflections back to the source. Further, the design causes high lead inductance and thus problems with power decoupling and may result in cross-talk with closely adjacent signal lines.
Johnson recently disclosed in U.S. Patents ~o. 5,069,629 (issued December 3, 1991) and ~o. 5,207,584 (issued ~ay 4, 1993) electrical interconnect contact systems which are directed to addressing both hAn;r~l and electrical cnn~ rAtions of such o systems. The disclosure of theæe references i5 incorporated herein by reference.
The disclosures of Johnson are directed to an interconnect device which comprises a generally planar contact which is received within one or more slots of a housing. In one; ' ~ t, each contact is of a generally S-shaped design and supported at two locations (the hook portions of the S) by a rigid first element and an el~stomeric second element. As disclosed, the Johnson electrical interconnect provides a wiping action which enables a good inter~ace to be A~ C l; ~h~r1 between the contact and the lead o of the integrated circuit, and between the contact and tF~rm;n~l~ on a printed circuit board. Further, Johnson discloses an electrical contact that can sustain high operating speeds, and provides a very short path of connection. Such a contact may have low inductance and low resistance, thereby m;n;rn;7;n~ the; ^~lAn,-e of the contact.
In recent years, the number of leads which may extend from one .
of the above referenced semi-conductor packages has sub6tantially increased. Integrated circuit technology has allowed the integration of several complex circuits onto a single integrated circuit. Often, hundreds of thousands of gates may be incorporated 05 into a single chip. A consequence of such integration is often a requirement that many input/output leads must extend from a corresponding semi-conductor package. To limit the overall .1; ci~n~:: of the semi-conductor package, the spacing between leads of many of the above referenced semi-conductor packages ha3 10 decreased. As a result thereof, the spacing between the contacts of a corresponding interconnect device has also decreased.
The decrease in spacing between contacts of an interconnect device has necessarily increased the capacitance therebetween.
Thus, a signal on a first contact of an interconnect device may 15 affect the signal on a second contact of the interconnect device.
This rhPnl is known as cross-talk. Cross-talk increases the noise on a contact, and thus adversely affects the reliability of the interconnect system.
Electromagnetic Interference (EMI) is another source of noise 20 which reduces the reliability of interconnect systems. Typically, a low background level of EMI is present in the environment.
Other, more obtrusive sources of EMI included IC tester3, computers, test equipment, cellular phones, television and radio signal3, etc. A11 of these sources of EMI should be considered 25 when testing higher performance integrated circuits.
Another consideration of interconnect devices is the impedance .
provided by the corresponding contacts. It i5 recognized that the interconnect path between, for example, a semi-oonduotor package lead and a terminal on a printed circuit board, should have a relatively high and stable bandwidth across all applicable os freguencies. That is, not only should the impedance of the interconnect system be minimized as disclosed in Johnson, but the -~Anre should also be controlled such that a relatively flat hAn~lrACC over all applicable frequencies exists.
To achieve a 6table bandpass, it is often important to have a 10 contact which providea i -~nre matching between a corresponding input of an integrated circuit and the corresponding driver. For example, if a tester is driving an input of an integrated circuit device via an interconnect device, it may be important for the interconnect device to provide an imr~rlAnre such that the i~r~rlAnre 15 of the driver matches the input i ~~~iAnr~ of the integrated circuit. Since the input i ~ Ance of the integrated circuit is often fixed, the impedance of the interconnect device may be used to correct for any i - ~Anre mis~match between the driver and the integrated circuit. Impedance matching may be important to 20 minimize reflections and other noise -hAni omc which may reduce the r~l i Ahi ~ i ty and accuracy of the corresponding system.
Accordingly, a need exists for an improved electrical interconnect system to be utilized for interconnecting integrated circuit devices with printed circuit boards or for interconnecting 25 multiple printed circuit boards. The interconnecting device should provide chiel~ling for both cross-talk and EMI. The interconnect 2 ~ 80578 .
deviee should also allow the user to control and/or select the impedance f or eaeh contact provided therein .
Summarv of the Invention The present invention addresses these needs as well as other 05 problems associated with prior art electrical interconnect systems.
The present invention provides an interconnect system whereby 2 number of contacts are shielded from outside sources of electro-magnetic interference by a conductive housing. Further, each of the contacts may be shielded from cross-talk interference between 10 adjacent contacts by conductive ribs extending therebetween.
Finally, the impedance of each contact in the interconnect system may be controlled to provide a stable bandpass, and the i - ~An~.P
may be !~L~JyL hle to match, or correct for, the input impedance of a corresponding device.
In an illustrative embodiment, the present invention provides an electrical interconnect between a number o~ first tprm;nAl~ and a number of second tP~m; n~ . The present invention may inelude a housing, a number o~ contacts, and a number of insulating elements.
Both the housing and the contacts are preferable made from a 20 conductive material. The insulating elements may insulate the number of contacts from the housing. By providing an electrically conductive housing, the contacts may be shielded from outside sourees of EMI. At the same time, however, because the contacts are electrically isolated from the housing, the contacts may 25 maintain an ;n-lepPn~1~nt interconnection between the number of first terminals and the number of second t~rlTinAl~i.
An addition advantage of the present invention is that the impedance seen by the contacts is stAhi 1 i 7~d and controlla~le. In the present invention, a controlled i -~Anre is created between 05 the contacts and the conductive housing. By varying the geometry of the contacts and the inRulating element, the impedance between the contacts and the housing can be ~IO ~L '. This may provide a stable, and controllable, bandpass for the signals passing through the interconnection system.
In addition to the above, the present invention contemplates s~hif~lrl;ng the upper and lower portions of the contacts that extend above and/or below the conductive housing. It is contemplated that this may be i~r~ h-~d in a nu~ber of ways, including providing a conductive skirt or gasket that is electrically coupled to the 15 housing, and may extend toward the first and/or second t~ n;nAl~
The conductive skirt may shield the upper and/or lower portions of the contacts from electro-magnetic interference from outside sources. In addition, and to shield each of the contacts from cross-talk interference from adjacent contacts, it is contemplated 20 that a number of ribs may be electrically coupled to the housing and may extend between adjacent contact. Selected ones of the number of ribs may extend above and/or below the top and/or bottom surf aces of the housing . The rib extensions may shield the top and/or bottom portions of the contacts from cross-talk 25 interference. Further, when the first or second terminal is a device lead, the rib extensions may shield cross-talk interference 21 80~78 between adjacent device leads, and between the device leads and ad j acent c ontact 8 .
Brief l)escriPtion of the ~)rawinq5 In the drawingfi, in which like reference numerals indicate 05 corresponding parts or elements of preferred ~ ; I s of the present invention throughout the several views:
Flgure 1 is a fragmentary perspective view showing a conductor between two parallel plates;
Figure 2 is a perspective view with some parts cut away 10 showing a first embodiment of the present, invention in combination with an integrated circuit and a printed circuit board;
Figure 3 is a perspective~ view showing a housing in accordance with the first ~Tnho~ nt of the present invention;
Figure 4 is a perspective view with some parts cut away 15 showing a second: ' o-l; 1 of the present invention in combination with a printed circuit board;
Figure 5 i8 a perspective view with some parts cut away showing a third: ' o~'; 7t of the present invention in combination with a printed circuit board;
Figure 6 is a perspective view showing a housing in accordance with the fourth: ~ l; 1 of the present invention;
Figure 7 is a side elevational view showing a housing in accordance with the first: ' -'; T-t of the present invention with a wire mesh placed over the top surface thereof;
Figure 8P. is a perspective view of an S-shaped contact as used 2 1 8057~
in the present invention;
Figure 8B is a perspective view of an S-shaped contact as used in the present invention with a predetermined portion removed therefrom;
05 Figure 8C is a perspective view of an S-6haped contact as used in the present invention with a number of predetermined portions removed theref rom;
Figure ga is a perspective view of a sleeve as used in the first: o~ t of the present invention with a predetermined portion removed therefrom;
Figure 93 is a perspective view of a sleeve as used in the f irst ' ~ of the present invention with a number of predetermined portion removed therefrom; and Figure 10 is a perspective view showing a housing in accordance with the first: o~ of the present in~ention, wherein a number of S-shaped contacts having varying impedance characteristics are preselected and placed within corresponding slots within the housing.
Detailed Descril~tion of the Invention Detailed r~mhr~ i 5 of the present invention are disclosed herein. Eiowever, it is to be understood that the disclosed embodiments are merely exemplary of the present invention wllich may be embodied in various systems. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative ba~is for .
teaching one of skill in the art to variously practice the invention .
Figure 1 i8 a fragmentary perspective view showing a conductor between two parallel plates. The diagram is generally showll at 10.
oS Figure 1 generally shows the relationship between the physical characteristics of an electrical contact structure and the resulting i ~ Pn~-e. A first plate 12 and a second plate 14 are shown extending substantially parallel to one another. A center plate 16 i3 disposed therebetween, wherein a dielectric or 10 insulating material 18 is provided between the center plate 16 and the f irst and second plates 12, and 14 .
For purposes of this discussion, it is assumed that center plate 16 is centered between ~irst plate 12 and second plate 14.
Thus, center plate 16 is positioned a distance "d" from first plate 15 12 and a same distance "d" from second plate 14. Center plate 16 has a length of "1" and a width o~ w as shown. Center plate 16, thus, has an area equal to '-w times ' 1 . The capacitance between center plate 16 and first plate 12 i5 generally given by the formula:
C = ~ A / D
wherein A is the area of center plate 16, D is the distance between center plate 16 and first plate 12, and ~ is the permittivity of dielectric 18. A ~imilar formula can be ~ound for the capacitance between center plate 16 and second plate 14. The corresponding 21 8~)578 .
- lAnre i3 generally expres6ed by the formula:
Z = 1 / (2~TfC) where f is the fre~uency.
It can readily be seen that the; -~Anre can be affected by oS varying the area of center plate 16, the distance between center plate 16 and first plate 12 and~or second plate 14, and the permittivity of dielectric material 18.
Flgure 2 is a perspective view with some parts cut away showing a first ' ~ L of the present invention in combination 10 with an integrated circuit 32 and a printed circuit board 34. The drawing i6 generally shown at 30. Integrated circuit 32 has a lead 38 which may electrically engage an S-shaped contact element 40.
A lower portion ( not shown ) of S-shaped contact element 4 0 may electrically engage a terminal 42 of printed circuit board 34.
15 The S-shaped contact element 40 is disposed within a slot within a housing 36. The construction of the S-shaped contact and the corresponding housing assembly 36 are described in U . S . Patent ~o .
5,069,629, issued to Johnson on December 3, 1991, w~lich is incorporated herein by reference. Although not sp-r;f;rAlly shown, 20 it is contemplated that any size, shape or type of contact element may be used in conjunction with the present invention. This inc:Ludes both rigid planer contact elements, deformable contact elements, or any other type of contact elements.
In the first embodiment of the present invention, housing 36 2 ~ 80578 i5 manufactured from a conductive material such as ~ minllm It is recognized, however, that housing 36 may be made from any conductive material. Elousing 36 has a number of slots dispo~ed therein, thereby forming a number of ribs therebetween. One such 05 rib is shown at 44. In a preferred e-mbodimentt the aluminum housing is manufactured from an aluminum blank. Each of the number of slots may be formed using an electro-discharge ~--hinill~ (EDM) process or a laser cutting process.
A sleeve 46 may be disposed in predetermined ones of the slots 10 of hou~ing 36. Each sleeve 46 may be manufactured from a dielectric or insulating material such as polytetrafluoroethylene.
Polytetraf luoroethylene is sold under the registered trademark ''Tl~FLO~'I9'' by Dupont Corporaticn. It is recognized, however, that any insulating material may be used to achieve the benefits of the 15 present invention. It is further recognized that a user may select an insulating material which has a desired permittivity value, thereby providing the desired impedance characteristics to a corresponding contact element. It is contemplated that the sleeves may be constructed as separate elements, or may be an electrically 20 insulative coating placed on the housing 36.
Each sleeve 46 may have a slot formed therein for receiving a corresponding contact. For example, sleeve 46 may have a slot 48 formed therein. Contact 40 may be disposed within slot 48 such that lead 38 may electrically engage an upper portion of contact 40 25 while terminal 42 may electrically engage a lower portion (not shown) of contact 40. Contact 40 may engage at least one elastomeric element as described in U.S. Patent No. 5,069,629, issued to Johnson on December 3, 1991.
51eeve 46 may provide electrical isolation between contact 40 and housing 36. Further, sleeve 46 may be r~r~ hl e. This may 05 be particularly useful after a prPd~tormined amount of wear occurs between the sleeve 46 and contact 40 due to friction and other damage ~h~n i cmq .
Since housing 36 may be made from a conductive material, housing 36 may provide EMI shielding to contact 40. Further, it i8 10 contemplated that housing 36 may shield integrated circuit 32 from noise generated on, or by, traces on printed circuit board 34.
Finally, rib 44 of housing 36 may minimize crosstalk between contact 40 and an adjacent contact 50.
It is contemplated that housing 36 may be grounded or 15 otherwise electrically connected to a known voltage. In thi3 configuration, the contact is surrounded by metal and an intervening dielectric, thereby yielding a strip-line structure.
The geometries and certain other physical parameters thus define the; - ~n, e of the contact elements.
In another ' `i L of the present invention, housing 36 may be formed from a plastic or other suitable dielectric or insulating material. Predetermined portions of housing 36 may then be coated or otherwise provided with a conductive surface. In a preferred , the inner 8urfaces of the ribs of housing 36 may be 25 coated to m;n~mi7e cross-talk between adjacent contacts. Further, it is contemplate that the top and side surfaces of housing 36 may l l 2t8057g .
be similarly coated to provide a shielding function. The conductive coating may be electrically coupled to ground.
An advantage of the~ ~mhr~; L shown in Figure 2 is that the impedance of contact 40 is known and stabilized. In some prior art 05 interconnect systems, the imrP~ nre of contact 40 may be dominated by stray capacitance and stray inductance, which may not terminate to a known voltage . The e ~nrl; r ~ -It shown in Figure 2 provides a ground plane and thus a majority of the impedance is terminated to ground. This may stabilize the bandpass of each contact up to the 10 cutoff freS~uency thereof.
With reference to Figure 1 and Figure 2, housing 36 provides a first plate (or rib) 44 and a second plate (or housing~ 36, with contact 40 disposed therebetween. The impedance, as seen by contact 40, is defined by the area of contact - 40, the distance 15 between contact 40 and rib 44 and housing 36, and the permittivity of sleeve 46. By varying these parameters, the i ~ '~nre of contact 40 may be designed to match, or correct for, the input -~ nre of the corresponding input of integrated circuit device 32. In an illustrative ~li nt, the diYtance between contact 40 20 and rib 44 is approximately 17 mils, but other distances are contemplated .
As indicated in U.S. Patent No. 5,069,62g, issued to Johnson, contact 40 is easily field replaceaole. That is, each contact 40 may be removed and replaced with another contact. Thus, it is 25 contemplated that a number of contacts, each having a different area, may be provided to a user along with a housing. The user may 21 8~578 .
determine the input impedance of each input of a corresponding integrated circuit. The user may then provide an appropriate contact into each slot within housing 36 such that the i ~ nre of each contact may match, or correct for, the input i ~n~ of the 05 corresponding inputs of the integrated circuit device. Thus, the user may: (1) determine t_e desired impedance of a contact element;
( 2 ) select a contact eLement that will result in the desired impedance; and (3) provide the contact selected in step (2) into a corresponding slot within a housing. In this way, a user may 10 program the i ~ ~n~-e of each contact within the interconnect device for each integrated circuit input, to be tested.
Flgure 3 is a perspective view showing a housing in accordance with the first ' ~ of the present invention. The drawing is generally shown at 60. A housing 61 comprising an electrically 15 conductive material is provided . In a pref erred embodiment, housing 61 is manufactured from ~ min1lm~ but it is recognized that any conductive material may achieve similar results. ~Iousing 61 may have a top surface 66 and a bottom surface 68 as shown. A
number of slots, for example slots 80,82, may be formed though 20 housing 61. Each of the slots 80,82 may extend from the top surface 66 through housing 61 to the bottom surface 68. As a result of forming the number o~ slots 80,82, a number of ribs may remain. For example, rib 84 may extend between slots 80 and 82.
Each rib 84 may be electro -hAnit-~l ly coupled to housing 61, 25 thereby providing an electrical shield around the perimeter of slots 80 and 82.

A sleeve may be provided within each of the slots. For example, sleeve 86 may be provided in slot 82. It is contemplated that sleeve 86 may be manufactured from an insulating or dielectric material such as polytetrafluoroethylene. Each sleeve may have a 05 slot formed therein for receiving a corresponding contact element.
For example, sleeve 86 may have slot 88 formed therein for receiving a corresponding contact element.
A contact may then be provided in each slot of predetermined sleeves. For example, contact 74 may be provided within slot 88 of 10 sleeve 86. In this configuration, sleeve 86 may electrically isolate contact 74 from housing 61. A8 indicated above, housing 61 may be electrically coupled to ground or to some other kno~
voltage. Since housing 61 is made from a conductive material, housing 61 may provide EMI shielding to each of the contacts as 15 shown. Further, the ribs of housing 61 may minimize crosstalk between adjacent contacts. Although not sp-~ if i~ y shown, it is contemplated that any size, shape or type of contact element may be used in conjunction with the present invention. This includes both rigid planer contact elements, deformable contact elements, or any 20 other type of contact elements.
Referring specifi-~1ly to housing 61, a first trough 62 may be provided in the top surface 66 thereof extending in a downward direction therefrom. A second trough 64 may be provided in the bottom surface 68 thereof extending in an upward direction 25 therefrom, wherein the first trough 62 is laterally offset from the second trough 64. A first support element Inot shown) may be .
disposed in the first trough 62 and a second support element (not shown) may be disposed in the second trough 64. The first and second support elements may be made from a rigid or elastomeric material. Each of the number of contacts may engage the first and oS second support members. A further discussion of the contact support structure may be found in U.S. Patent ~o. 5,069,629, issued to Johnson on December 3, 1991.
In a preferred; ' ~i- L, one or both of the first and second support elements (not shown~ are made from an elastomeric material.
10 This allows each of the contact elements to move both laterally and vertically when engaged by a device lead. The movement of the contacts may provide a wiping action to both the leads of an integrated circuit and the t~rminAlq of a printed circuit board.
The ' I~Air-nt shown in Figure 3 allows the desired contact motion 15 while maintaining a relatively constant i -~An,~o.
The ~ i- L shown in FLgure 3 has the advantage that the irrr~lAn-~e of each contact may be known and sl-Ahi 1 i 7r~d as described with reference to Figure 2. Thus, it is contemplated that a number of contacts, each having a different area, may be provided to a 20 user. The user may determine the input ;~re~lAn~ e of each input of a corresponding integrated circuit. The user may then select and provide an appropriate contact into each slot within housing 61 such that the ;rre~An~-e of each contact may match, or correct for, the input; ^~lAn~ e of the corresponding inputs of the integrated 25 circuit device. Thus, the user may: (1) determine the desired -~An~-e of a contact element; (2) select a contact element that 2 l 80578 .
will result in the desired impedance; and (3) provide the contact selected in step (2) into a culLe~j~u~ding slot within a housing.
- In this way, a user may program the ;mr~rlAnf e of each contact within the interconnect device for each integrated circuit input to be tested.
05 Figure 4 is a perspective view with some parts cut away showing a second ~ ; l. of the prese~t invention in combination with a printed circuit board. ~he diagram is generally shown at 100. A housing 102 is provided. It is contemplated that housing 102 may be formed from an electrically conductive material.
Although Alllminllm is the preferred material, it is recognized that any electrically conductive material may achieve similar results.
~Iousing 102 may have a number of slots 104,106 formed therein.
Each slot 104 and 106 may be separated by a rib 108. Rib 108 may be electro ----hAni~ Al ly coupled to housing 102. Each slot may have at least one spacing member 110 disposed therein. In the -~;r-nt shown in Figuro 4, slot 104 has four spacing members 110, 112, 114, and 116 disposed therein. Each of the four spacing members 110, 112, 114, and 116 may be positioned in one of the four corners of slot 104. ~hus, spacing member 110 is laterally spaced from spacing member 112. Similarly, spacing member 114 is laterally spaced from spacing member 116. In a preferred ir L/ spacing members 110, 112, 114, and 116 may be formed from polytetrafluoroethylene. It is recognized, however, that a user may select an insulating material which has a desired 25 permittivity thereby providing the desired ; -~-n- e .
characteristics to a corresponding contact element.
A contact 120 may be provided within slot 104 such that an upper portion of contact 120 is positioned between spacing members 110 and 112, and a lower portion of contact 120 is positioned oS between spacing members 114 and 116. In this configuration, contact 120 is prevented from electrically contacted a sidewall of slot 104. Furthermore, the dielectric material extending between contact 120 and rib 108 and housing 102 is substantially comprised of air, except for the portions of contact 120 which engage spacing 10 members 110, 112, 114, and 116. It is known that air has a low permittivity value and therefore may minimize the capacitance between contact 120 and rib 108 and housing 102. This may increase the bandpass and/or cut-off frequency of contact 120.
Figure 5 is a perspective view with some parts cut away 15 showing a third - ; t of the present invention in combination with a printed circuit board. The drawing is shown generally at 140. This ~mhn~l; nt is similar to the n~ t shown in Figure 4 except the spacing members 110, 112, 114, and 116 are removed.
Rather, each contact 142 and 144 may have an insulating layer 20 provided directly on the lateral outer surfaces thereof. For example, contact 142 may have a first insulating layer 146 provided on a first surface thereof and a second insulating layer 148 on a second surface thereof. ~t is contemplate that the first and second insulating layers 146 and 148 may be provided on contact 142 25 via an adhesive, a deposition process, a subtractive process, or any other means. The first insulating layer 146 and the second insulating layer 148 may prevent contact 146 from electrically contacting housing 150. The same attendant advantages f7; ~c~ od above may be provided by this ~ ; r nt as well .
Figure 6 is a perspective view showing a housing in accordance 05 with a fourth embodiment of the present invention. The diagram is generally shown at 170. This ' - '; nt is related to the first embodiment shown and describe with reference to Figure 3. Elowever, in this -~l;r t, it is contemplated that preselected rib3 of the housing may extend upward beyond the top surface of the housing and L0 toward a u ulLe,.~u~ding integrated circuit device as shown. For example, ribs 178, 180, and 182 may extend above top surface 174 of housing 172. As indicated above with reference to Figure 2, a lead of an integrated circuit may ~electrG -hAnir Ally engage each of the contacts. For example, a lead of an integrated circuit may 15 electro-~ -hAnirAlly engage contact 184. Thus, the lead of the integrated circuit may pass in between ribs 180 and 182. ~ibs 180 and 182 may thus provide electro-magnetic ~h;r~ ;n~ to the top portion of contact 184 and to at least a portion of the u vL~ onding lead (not shown). Further, the impedance matching 20 effects discussed above may be applied to both the contact 184 and the corresponding lead (not shown).
Another f eature of the r~rhnrl; r L shown in Figure 6 is an EMI
skirt provided along the bottom perimeter of housing 172. It is contemplated that a skirt 190 may be provided between housing 172 25 2nd a corresponding printed circuit board. Skirt 190 may be formed from any conductive material. Tdowever, in a preferred ' -Ifiir-nt~

2 1 805;7~3 .
skirt 190 may be formed from a wire mesh which may be compressed a~
housing 172 is brought into engagement with a corresponding printed circuit board (not shown). Skirt 190 may provide EMI ~h;F.1~1in~ to the lower portion of the contacts and/or the t~rmin~lc on the 05 printed circuit board.
Another f eature of the l~ho~l i L shown in F$gure 6 is a conductive gasket 192. It is contemplated that conductive gasket 192 may be provided between housing 172 and a corresponding printed circuit board. Conductive gasket 192 may be formed from any 10 conductive material. In a preferred embodiment, however, conductive gasket 192 may be f ormed f rom a metallic material or a wire mesh. Conductive gasket 192 may provide EMI ~;hi~ ling to the lower portion of the contacts and~or the tc~rm; n:~ l s on the printed circuit board. It is contemplate that skirt 190 and conductive 15 gasket 192 may be used together or individually, depending on the particular application.
Figure 7 is a side elevational view showing a housing in accordance with the first embodiment of the present invention with a wire mesh placed over the top surface thereof. The diagram is 20 gener211y shown at 200. A housing 202 may be provided, wherein the housing may be made from a conductive material such as aluminum.
It i5 recogni2ed, however, that any conductive material may be used for housing 202.
As described with reference to Figure 3, a number of contacts, 25 for example contact 204, may be received within a number of slots.
A sleeve may be provided in each of the number of slots within the 2 ~ 80578 housing 202. The construction of the contact, sleeve, and housing is further described with reference to Figure 3.
An integrated circuit device 206 having a number of leads, may be brought into electL., ~ -hAn;r Al ~n~a:, nt with the number of 05 contacts of the interconnect device. For example, lead 208 of integrated circuit device 206 may be brought into electro-hAni~ Al engagement with contact 204 of the interconnect device.
The lower portion of selected contactg may be in electlU - -h:~n;~-Al engagement with selected t~rmi nAl ~ on a printed circuit board.
10 Thus, the interconnect device 200 may electlu - -hAnirAl ly couple a lead of integrated circuit device 206 with a corresponding terminal on a printed circuit board.
It is contemplated that an offset 207 may be positioned between housing 202 and integrated circuit device 206. In a preferred ~; L, offset 207 may be part of housing 202 and may be made from a conductive material. Since housing 202 may be grounded, offset 207 may provide a direct ground connection to integrated circuit device 206. This may be particularly useful when integrated circuit device 206 is packaged such that a ground 20 plane thereof is positioned adjacent offset 207. Further, offset 207 may provide a thermal sink to integrated circuit device 206.
Finally, offset 207 may provide a body stop to prevent damage to the leads 208 of integrated circuit 206 and to contacts 204.
In the ~ shown in Figure 7, a conductive mesh 210 may 2 be provided over the top of integrated circuit device 206. The conductive mesh may be electrically connected to the outer .
periphery or other predefined portion of housing 202. It is contemplated that conductive mesh 210 may be a wire mesh. It i8 further contemplated that conductive mesh 210 may comprise a conductive cover or similar structure which is electrically coupled 05 to housing 202. A purpose of conductive mesh 210 is to pro~ide EMI
shielding to the upper portion of the contacts, the leads of the integrated circuit device 206, and the integrated circuit device 2 0 6 itself .
The density of the wire mesh may vary rl~r~nrl;nq on the particular application. For example, the density of the wire me3h may be lower if only relatively low frequency EMI i5 to be ~:h; ~ rl . Conversely, the density of the wire mesh may be higher if relatively high frequency~EMI is be shielded. Thus, the wire mesh may be ~l-si~n-~cl to a~c, ':~te a wide variety of applications.
Figure 8A is a side perspective view of an S-shaped contact as used in the present invention. The diagram is generally shown at 220. In a preferred ~mh~ t, a contact 222 is S-shaped and ~i R;~lnF-~l such that a first hook portion 224 engages a first support member (not shown) and a second hook portion 226 engages a second support member (not shown). In a preferred ~rnh~
contact 222 is formed from a beryllium-copper alloy. A further discussion of the contact support structure may be found in U.S.
Pztent No. 5,069,629, issued to Johnson on December 3, l991.
With ref erence to Figure 1, the capacitance of a contact element is generally given by the formula C = A / D. The area of contact 222 is defined by a contact length 230 and a contact 2 l 80578 .
width 228. In a preferred '-'; ~, the contact 222 is dimensioned to maintain the position of the first and second hook portions 224, 226. This may be necessary to allow the first and second hook portions 224, 226 to physically engage the first and5 second support members (not shown~. In one -~i 1., this may be hPd by substantially maintaining the contact lensth 230.
Thus, it is contemplated that the iTnrprlAnre of the contact element 222 may be varied by reducing the contact width 228 or varying other design parameters of contact 222.
It is contemplated that a number of contacts, each having a different area as described above, may be provided to a user. The user may determine the input impedance of each input of a corresponding integrated circuit. The user may then provide an appropriate contact into each slot within a housing such that the 15 ; _ - ~ ln~ e of each contact may match, or correct for, the input impedance of the corresponding inputs of the integrated circuit device. Thus, the user may: ~1) determine the desired; _-9Ance of a contact element; (2) select a contact element having the desired impedance; and ( 3 ) provide the contact selected in step ( 2 ~ into a 20 Corrpcr~n~l;n~ slot within a housing. In this way, a user may program the ; _ -~An~ P of each contact within the interconnect device for each integrated circuit input to be tested.
It is further recognized that the distance from the contact to a corresponding rib may be varied to change the ; _ - ~Ance of a c~,L~ onding contact. This may be ~-c~ _ 1 i Cllpd by changing the thickness of the contact or providing a larger distance between adjacent ribs in the housing. Further, it is recognized that the permittivity of a corresponding sleeve may be varied by substituting various materials therefor to change the impedance of a ~JLL~ oding contact. As indicated with reference to Figuro 4, 05 it has already been disclosed that air may be used as an insulating material. Other materials are also contemplated.
Fisure 8B is a side perspective view of an S-shaped contact as used in the present invention with a predetermined portion removed therefrom. The diagram is generally shown at 240. A contact 10 element 242 having a removed portion 244 may be provided. The removed portion 244 may reduce the overaLl area of contact element 242. As indicated with reference to Figure 8A, it is preferred that the position of the first and second hook portions 246 and 248 remain relatively fixed because the first and second hook portions 246, 248 must physically engage the first and second support members (not shown). In the ' ~li t shown in Figure 8B, the outer ~;~ q;nnq of contact element 242 are substantially the same as the outer dimensions of contact element 222 of Figure 8A. The ~ n~e of contact element 242 may be varied by removing a 20 predetermined portion of contact element 242 as shown. It is contemplated that any portion of contact element 242 may be removed as long as the position of the first and second hook portions 246, 24 8 remains relatively f ixed .
Figuro 8C is a sidc perspective view o~ an S-shaped contact as 25 used in the present invention with a number of prP~lptprm;np~l portions 261 removed therefrom. The diagram is generally shown at .
260 wherein a contact element 262 is shown. This Pmhorl; L is similar to the structure shown in Figure 8EI. Eowever, rather than removing a single portion from the contact element, it i8 contemplated that a number o portions may be removed from contact 05 element 262 as shown. This may reduce the overall area of contact element 262.
As indicated with reference to Figure 8A, it is preferred that the position of the first and second hook portions 264 and 266 remain relatively fixed because the first and second hook portions 264, 266 must physically engage the first and second support members (not shown). In the ~ nt shown in Figure 8C, the outer f1; c;nll~ of contact element 262 are substantially ~:he same as the outer dimensions of contact elements 222 and 242. The - ~Ar~re of the contact element 262 may be varied by removing a 15 number of predetermined portions from contact element 262 as shown.
It is contemplated that any number of portions may be removed from contact element 262 as long as the position of the first and second hook portions 264, 266 remains relatively fixed.
Figure 9A is a perspective view of a sleeve as used in the 20 first embodiment of the present invention with a predetermined portion removed therefrom. The diagram is generally shown at 300.
In a preferred PTnhO~il L, sleeve 302 is positioned within a corresponding slot within a housing. Since it is contemplated that the slots in the housing may be uniformly dimensioned, it is 25 desired that each sleeve 302 have the same outer dimensions.
With ref erence to Figure 1, the capacitance of a contact 2 ~ 80578 element i8 given by the formula C = E ~ D. The sleeve 302 may be made from an insulating material having a preselected permittivity. Thus, the impedance of a contact element may be varied by changing the permittivity of the dielectric or insulating 05 material which is disposed between the contact element and the housing. In the embodiment shown in Figure 9A, a portion 304 may be removed from sleeve 302. Thus, the permittivity of the area between the contact element and the housing is defined by the insulating material for part of the contact area, and de~ined by 10 air for the L~ in;nrJ contact area. By ri; q;rn;n~ the portlon 304 that is removed from sleeve 302, a desired; _-~n~ e may be selected for each contact in the interconnect device.
It is contemplated that a number of sleeves, each having a different sized removed portion, may be provided to a user. The 15 user may determine the input; ~ nre of each pin of a corresponding integrated circuit. The user may then insert an appropriate sleeve into each slot of the housing such that the impedance of each contact may match, or correct for, the input impedance of the corresponding inputs of the integrated circuit 20 device. Thug~ the user may: (1) determine the desired; ~ nre of a contact element; (2) select a sleeve that will result in the desired i _-~n.-e; and (3~ provide the sleeve selected in step (2) into a corresponding slot within a housing. In this way, a user may program the ~ ~nre of each contact within the interconnect 25 device for each integrated circuit input to be tested.
Figure 9B i8 a perspective view of a sleeve as used in the ~ 2 1 80578 first ~ 'i t of the preseDt invention with a number of predetermined portions removed therefrom. The diagram is gener211y shown at 310 wherein a sleeve 312 is shown. This ~ L i~
similar to Figure 9A. ~owever, rather than removing a single portion from the sleeve, a number of predetermined portions 311 may 05 be removed, as shown.
Figure 10 is a perspective view showing a housing in accordance with the first ' ofl; L of the present invention, wherein a number of S-shaped contacts having varying; ~ Anre characteristics are preselected and inserted within corresponding slots within the housing. The diagram is generally shown at 330.
A housing 332 comprising an electrically conductive material i~
provided and is sub~tantially similar to that shown and de~cribed with reference to Figure 3. A number of slots, for example slots 334,336, and 338, may ~e formed though housing 332. As a result of forming the number of slots 334,336, and 338, a number of ribs remain therebetween. For example, rib 340 may extend between slots 334 and 336. Each rib 340 is electro --chAnir~ y coupled to housing 332, thereby providing an electrical shield around the perimeter of each of the slots.
A number of sleeves may be provided within each of the slots.
For example, sleeve 344 may be provided in slot 338. It is contemplated that sleeve 344 may be manufactured from an insulating or dielectric material. Each sleeve may have a slot formed therein for receiving a corresponding contact element. For example, sleeve 344 may have slot 346 formed therein for receiving a corresponding . . 2~80578 contact element 343.
A preselected contact may then be provided within each of the 310ts of the number of sleeves. For example, contact 34~ may be provided within slot 346 of sleeve 344. In this configuration, 05 sleeve 344 electrically isolates contact 346 from housing 332. In a preferred ombodiment, housing 332 is electrically coupled to ground or to some other known voltage. Since housing 332 i~ made from a conductive material, housing 332 may provide EM3 chiPl~;n~
to each o_ the contacts therein. Further, the ribs of housing 332 may minimize crosstalk between adjacent contacts.
Rcferring sr~i fit'Al ly to the: ' oAi~ ~t shown in FLguro 10, it is contemplated that a number of contacts 348,350,352, each having a different area and thus a different ; -~sn~e characteristic, may be provided to a ~ser o~ the interconnect device. The user may determine the input impedance of each input of a corresponding integrated circuit. The user may then provide ~n appropriate contact, as shown, into each slot within housing 332 such that the i ~ ~nre of each contact may match, or correct for, the input i ~ n~ e of the corresponding inputs of the integrated circuit device. Thus, the user may: (1) determine the desired imr-~d;~n--e of a contact element; (2) select a contact element that will result in the desired impedance; and (3) provide the contact selected in step ( 2 ) into a corresponding slot within the housing .
In this way, a user may program the irr~erl~nl-e of each contact within the int~l~u~ e~L device for each integrated circuit input to be tested.

2 1 8~578 --.
It i9 further contemplate that the user may: (1) determine the desired i -~nre of a contact element; (2I select a sleeve that - will result in the desired i ~ n~ e; and (3) provide the sleeve selected in step (2) into a corr~sp~nr7~nq slot within a housing.
05 ~n this way, a user may program the i ~ n~e of eac~ contact within the interconnect device for each integrated circuit input to be tested.
Finally, it is contemplated that a user may: (l) deteL-mine the desired ~ ~ 1Anre of a contact element; (2) select a sleeve and 10 contact combination that will result in the desired i ~ n~ e; and

(3) provide the sleeve and contact combination selected in step (2) into a corresponding slot within a housing. This may provide additional flexibility in achieving the desired contact i - 'Anr~e.
~ew characteristics and aavantages of the invention covered by 15 this document have been set forth in the foregoing description. It will be understood, however, that this disclosure is, in many respects, only illustrative. Changes may be made in details, particularly in matters of shape, size, and arrangement of parts, without .oY~-e--~inq the scope of the invention. The scope of the 20 invention is, of course, defined in thc language in which the p~n~d claims are expressed.

Claims (32)

What is claimed is:

1. Apparatus for electrically interconnecting a first terminal to a second terminal, comprising:
(a) housing means, wherein at least a portion of said housing means is electrically conductive;
(b) insulating means; and (c) contacting means for contacting the first terminal to the second terminal, said insulating means electrically insulating said contacting means from said housing means.

2. Apparatus for electrically interconnecting a first terminal to a second terminal, comprising:
(a) a housing having a portion which is electrically conductive, said housing having a number of slots formed therein;
(b) a sleeve provided in a preselected one of said number of slots of said housing and having a portion which is electrically insulative, said sleeve forming a contact receiving slot; and (c) a contact disposed in said contact receiving slot formed by said sleeve, at least a portion of said contact being electrically conductive, and said sleeve electrically insulating the portion of said contact that is electrically conductive of said contact from the portion of said housing that is electrically conductive;
(d) whereby when said first terminal and said second terminal engage said contact, said contact electrically connecting said first terminal to said second terminal.

3. Apparatus according to claim 2 wherein said housing has an outer surface, and a portion of said outer surface is formed from a conductive material.

4. Apparatus according to claim 3 wherein said entire housing is formed from a conductive material.

5. Apparatus according to claim 2 wherein said sleeve is of a singular construction.

6. Apparatus according to claim 2 wherein said sleeve comprises a number of spacing members.

7. Apparatus according to claim 2 wherein said contact has a number of holes therein.

8. Apparatus according to claim 2 wherein said housing includes a first slot and a second slot, and the first slot is located adjacent to the second slot with a rib extending therebetween.

9. Apparatus according to claim 8 wherein at least a portion of said rib is electrically conductive.

10. Apparatus according to claim 9 wherein said portion of said rib that is electrically conductive is electrically coupled to said housing.

11. Apparatus according to claim 10 wherein said rib has a first surface forming part of said first slot and a second surface forming part of said second slot.

12. Apparatus according to claim 11 wherein at least a portion of said first surface of said rib is electrically conductive.

13. Apparatus according to claim 11 wherein at least a portion of said first surface is coated with a conductive material.

14. Apparatus according to claim 12 wherein at least a portion of said second surface of said rib is electrically conductive.

15. Apparatus according to claim 13 wherein at least a portion of said surface is coated with a conductive material.

16. Apparatus according to claim 2 wherein said sleeve includes a number of holes extending through a portion thereof, wherein said number of holes are positioned generally between said housing and said contact.

17. Apparatus according to claim 8 wherein said housing has a top surface and a bottom surface, and said first and second slots extend between said top surface and said bottom surface.

18. Apparatus according to claim 17 wherein said rib extends upward from said top surface of said housing.

19. Apparatus according to claim 2 wherein said housing includes a top surface and a bottom surface, wherein the top surface is adjacent the first terminal and the bottom surface is adjacent the second terminal.

20. Apparatus according to claim 19 further comprising an electrically conductive skirt, wherein said electrically conductive skirt is electrically coupled to said housing and extends downwardly from said bottom surface of said housing toward said second terminal.

21. Apparatus according to claim 20 wherein said second terminal is a conductive pad on a printed circuit board.

22. Apparatus according to claim 21 wherein said skirt extends downwardly from said bottom surface of said housing and to said printed circuit board.

23. Apparatus according to claim 19 further comprising an electrically conductive gasket, wherein said electrically conductive gasket is electrically coupled to said housing and extends downwardly from said bottom surface of said housing toward said second terminal.

24. Apparatus according to claim 19 further comprising a conductive skirt, wherein said conductive skirt is electrically coupled to said housing and extends upwardly from said top surface of said housing toward said first terminal.

25. Apparatus according to claim 24 wherein said second terminal is a device lead of a device package.

26. Apparatus according to claim 25 wherein said conductive skirt extends upwardly from said top surface of said housing and around said device package.

27. Apparatus for electrically interconnecting a first terminal to a second terminal, comprising:
(a) a housing, said housing having a portion which is electrically conductive, said housing further having a number of contact receiving slots formed therein;
(b) a contact disposed in a selected one of the number of contact receiving slots, wherein a portion of said contact is electrically conductive; and (c) an insulating layer disposed between at least the portion of said contact that is conductive and the portion of the housing that is conductive;
(d) whereby as the first terminal and the second terminal are brought into engagement with said contact, said contact electrically connects said first terminal to said second terminal.

28. Apparatus according to claim 27 wherein said contact has an outer surface, and at least a portion of said outer surface is electrically conductive.

29. Apparatus according to claim 28 wherein said insulating layer is disposed on at least a portion of the outer surface of said contact such that the portion of said outer surface that is electrically conductive is electrically insulated from the portion of said housing that is conductive.

30. A method for configuring an interconnect device, wherein the interconnect device includes a housing and a number of contacts, the housing having a number of contact locations wherein at least one contact is mounted at selected ones of the number of contact locations, the method comprises the steps of;
(a) providing a number of contacts wherein each of the number of contacts provides a different impedance when mounted in a selected one of the number of contact locations of the housing;
(b) determining a desired impedance for selected ones of the number of contact locations of the housing;
(c) selecting a contact from the number of contacts that provides the desired impedance for each of the contact locations of the housing; and (d) mounting the selected contacts into the corresponding contact locations of the housing.

31. A method for configuring an interconnect device, wherein the interconnect device includes a housing, a number of sleeves, and a number of contacts, the housing having a number of contact locations wherein at least one of the number of sleeves is mounted at selected ones of the number of contact locations, and at least one of the number of contacts is mounted in corresponding ones of the number of sleeves, the method comprises the steps of;
(a) providing a number of sleeves wherein each of the number of sleeves provides a different impedance between a corresponding contact and the housing when mounted in a selected one of the number of contact locations of the housing;
(b) determining a desired impedance for selected ones of the number of contact locations of the housing;
(c) selecting a sleeve from the number of sleeves that provides the desired impedance for each of the contact locations of the housing; and (d) mounting the selected sleeves into the corresponding contact locations of the housing, and mounting at least one contact in each of the selected sleeves.

32. A method for configuring an interconnect device, wherein the interconnect device includes a housing, a number of sleeves, and a number of contacts, the housing having a number of contact locations wherein at least one of the number of sleeves is mounted at selected ones of the number of contact locations, and at least one of the number of contacts is mounted in corresponding ones of the number of sleeves, the method comprises the steps of;
(a) providing a number of sleeves wherein each of the number of sleeves provides a different impedance between a corresponding contact and the housing when mounted in a selected one of the number of contact locations of the housing;
(b) providing a number of contacts wherein each of the number of contacts provides a different impedance when mounted in a corresponding one of the number of sleeves;
(c) determining a desired impedance for selected ones of the number of contact locations of the housing;
(d) selecting a sleeve and contact combination from the number of sleeves and the number of contacts that provides the desired impedance for each of the contact locations of the housing; and (e) mounting the selected sleeves into the corresponding contact locations of the housing, and mounting the selected contacts in the corresponding ones of the selected sleeves.